Process for splitting a narrow film or false twisting a fibrous material



Jan. 13, 1970 NOBUJI ASAKA 3,488,941

PROCESS FOR SPLITTING A NARROW FILM OR FALSE TWISTING A FIBROUS MATERIAL Filed Dec. 1, 1967 3 Sheets-Sheet l Jan. 13, 1970 NQBUJI' ASAKA 3,488,941

PROCESS FOR SPLITTING A NARROW FILM OR FALSE TWISTING A FIBROUS MATERIAL Filed Dec. 1, 1967 3 Sheets-Sheet 2 Jan. 13, 1970 NOBUJI ASAKA 3,488,941

PROCESS FOR SPLITTING A NARROW FILM OR FALSE TWISTING A FIBROUS MATERIAL Filed Dec. 1, 1967 3 Sheets-Sheet 5 United States Patent 3,488,941 PROCESS FOR SPLITTING A NARROW FILM 0R FALSE TWISTING A FIBROUS MATERIAL Nobuji Asaka, Ibaragi-shi, Japan, assignor to Teijln Lunited, Osaka, Japan, a corporation of Japan Filed Dec. 1, 1967, Ser. No. 687,294 Claims priority, application Japan, Dec. 5, 1966, 41/79,741; Feb. 7, 1967, 42/7,811, 42/7,812; Apr. 14, 1967, 42/215,797, 42/23,798; May 2, 1967, 42/27,977

Int. Cl. D02g 3/02; D01h 7/92, 7/46 US. Cl. 57157 8 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a process for false twisting a continuous thin, narrow film of a thermoplastic linear high polymer or a continuous fibrous material of said polymer. More particularly, the present invention relates to a process for false twisting said film or said fibrous material by passing the same between frictionally overlapped surfaces of two rotating surfaces of the same diameter rotating in mutually different directions while frictionally contacting face by face.

An object of the present invention is to provide a novel, eflicient process for preparing various modified yarns such as split fibers or bulky yarns using a continuous narrow film or continuous fibrous material.

Other objects of the present invention will become clear from the following explanation.

In accordance with the present invention, said objects and advantages are achieved by passing a continuous thin, narrow film or continuous fibrous material consisting of a thermoplastic linear high polymer between frictionally overlapped surfaces of two rotating surfaces of the same diameter rotating in mutually different directions along the rotating direction of said overlapped surfaces substantially on the bisecting line of said overlapped surfaces.

The term continuous thin, narrow film as used in this specification includes a long material of any shape as long as it is continuous and thin, such as a ribbon, band, foil or tube, While the term continuous fibrous material includes all the continuous fibrous material, such as continuous spun yarn, continuous multifilament yarn, continuous filaments and tows.

In order to facilitate understanding of the present invention, the present invention will be explained with reference to the drawings. However, it should be noted that the drawings illustrate a few embodiments included in the present invention and will not restrict the present invention.

In the accompanying drawings:

FIG.-1-is a perspective view showing one embodiment of contact of two rotating bodies which can be used in the present invention.

FIG. 2 is a sectional view taken along dotted line II' in FIG. 1.

Patented Jan. 13, 1970 "ice FIG. 3 is a side elevation of another embodiment of rotating bodies used in the present invention.

FIG. 4 is a sectional view taken along dotted line IIII' in FIG. 3.

FIG. 5 is a schematic view illustrating an action received by a long material to be treated between overlapped surfaces of two rotating bodies of the same diameter.

- FIGS. 6 and 7 are schematic views showing the relationship between frictionally contacted surfaces and axial distance of two annular rotating friction bodies.

FIG. 8 is a diagrammatic view showing one embodiment of an apparatus employed when the process of the present invention is utilized for preparation of a split yarn.

FIG. 9 is a diagrammatic view similar to FIG. 8 showing one embodiment of an apparatus employed when the process of the present invention is utilized for preparation of a bulky yarn.

At first an explanation will be made with reference to FIGS. 1 and 2.

The tip of a rotating shaft 1 forms a circular flange 2 on which a circular disc 7 is screwed by bolts 4; into said circular disc 7, a circular friction body 3 having an annular rim for-med by, for instance, proper synthetic rubber is inserted, which body 3 is tightly adhered to said circular disc 7 with an adhesive and the entirety constitutes a rotating body 5. Another rotating body 5' is constituted by members of shape and quality same as those of said rotating body 5, the corresponding members of the rotating body 5' being shown by the same numbers of the members of the rotating body 5 added with dashes. Accordingly, the rotating bodies 5 and 5' are of the same diameter. As illustrated in the drawings, the rotating bodies 5 and 5' are so constituted that peripheries of the outer surfaces of the respective circular friction bodies 3, 3' rotate in opposite directions while contacting face by face at a proper width. Numeral 6 shows a cross section of a continuous narrow film or continuous fibrous material to be treated.

FIGS. 3 and 4 show the structures of a rotating body of structure different from that of the rotating body of FIGS. 1 and 2, but also usable in the practice of the present inventlon.

Rotating bodies 15, 15' of FIGS. 3 and 4 are rotating bodies of the entirely identical diameters. To the outer peripheral surfaces of the respective annular rims of metal bowl-shaped members 12, 12' having annular rims screwed to the respective rotating shafts 11, 11' by bolts 14, 14', annular friction bodies 13, 13 are tightly adhered with a proper adhesive and the rotating bodies 15, 15' are so constituted that they may rotate in mutually opposite directions while the annular outer peripheral surfaces of said annular friction bodies 13, 13' contact with overlap as shown in FIG. 4.

For practicing the present invention using these apparatuses, a continuous narrow film or continuous fibrous material is inserted between surfaces contacted face by face of the respective rotating bodies 5, 5 shown in FIGS. 1 and 2 or 15, 15' shown in FIGS. 3 and 4, and while said continuous narrow film or continuous fibrous material is located so as to pass on the substantially bisecting line of contacted frictional overlapped surfaces of said rotating bodies as shown by line AB in FIG. 4 along the rotating direction of said overlapped surfaces, the rotating bodies 5, 5' or 15, 15' are rotated in mutually opposite directions. Then said continuous narrow film or continuous fibrous material receives rotating frictional' action of the respective friction surface of said two rotating bodies throughout the entire distance between'the points A and B. Action received by said film or fibrous material at this time will be explained in detail hereinbelow with reference to FIG. 5.

Two circles shown in FIG. 5 diagrammatically stand for the two circular rotating bodies partially overlapped and rotating in mutually opposite directions as used in he present invention. Centers of the two circles are made 3, O, crossing points of the two circles are made A and 3, respectively, and crossing point of line AB and the :entral line 0, O is made C. An optional point on line B is made D, and OA=a, C=b, OD=x and When the number of rotations of the circular rotating )ody is made n, a, b, on and n are constants while x is a zariable.

The proceeding path of the film or fibrous material is, [S mentioned above, line AB, and, feeding speed and wisting speed of the film or fibrous material on the opional point D On line AB equal to a component of elocity DF in a direction parallel to the proceeding diection of the film or fibrous material and a component )f velocity DG in a direction perpendicular to said pro- :eeding direction of the rotating velocity DE at the point of the rotating body, respectively.

(i) The feeding speed DF of the film or fibrous mateial at the optional point is given by the following equalOIl.

In said equation, since both b and n are constants, .the Feeding speed of the film or fibrous material at any and ll]. points on line AB is constant.

(ii) The twisting speed DG of the film or fibrous mate- 'ial at the optional point is given by the following formula.

As will be apparent from the above equation, the twistng speed of the film or fibrous material becomes maximum at the point A, gradually decreasing therefrom, lecoming minimum at the point C, namely zero. After |assing the point C direction of the twisting speed .is nversed, and said speed gradually increases, becoming maximum at the point B.

(iii) Number of twists per unit time of the film or ibrous material at the optional point is given by the ollowing equation.

vherein 6 stands for an apparent diameter when the film r fibrous material is twisted.

(iv) When number of twists per unit length of the ,lm or fibrous material at the optional positions is exressed by T, T is obtained by dividing number of twist er unit time at the optional position of the film or fibrous iaterial by feeding speed at that point, namely, it is iven by the following equation.

arm/55 1 ve -m As will be apparent from this equation, the number of wists per unit length of the film or fibrous material is iaximum when x=a, becoming zero when x=b.

Now, in FIG. 5 when the situation of the film or brous material twisted is observed, prior to the point l, twist T represented by the equation disseminated. In case of FIG. 5, direction of twist is y direction. Between A and C in FIG. 5, number of twists f the film or fibrous material gradually decreases, be-

coming zero at the point C. Direction of twist between A and C is also Z direction.

Between C and B, rotating direction of the circular rotating body is inverted, number of twist is zero at the point C, becoming maximum at the point B. However, because the rotating direction is inverted, direction of twist becomes S direction. After the film or fibrous material leaves the point B, in accordance with the principle of false twisting the film or fibrous material is untwisted to Zero point and comes out.

As explained above, in the process of the present invention, when a long material is treated with the point C in FIG. 5, namely, center of the bisecting line of overlapped surfaces of the two circular rotating surfaces of the same diameters as a border, contrary frictional actions in S and Z directions are imparted and as shown by vectors D6 and DF, throughout the entire period such long material passes between said overlapped surfaces a feeding action along the direction of length and a frictional action from a direction perpendicular thereto, namely, a transverse direction are imparted thereto. Therefore, in the process of the present invention, a long material to be treated is held between said overlapped surfaces during the period it passes therebetween, and said material is positively forwarded in its proceeding direction, and at the same time, with the center of said overlapped surfaces as a border, said material undergoes twist and rubbing action from left and right directions thereby being false twisted.

Utilizing the aforementioned action, according to the present invention, it is possible to prepare various modified yarns such as bulky yarn or split yarn from a continuous narrow film or continuous fibrous material. When a long material to be treated, for instance, a plurality of filaments of a continuous narrow film or continuous multifilament is adapted to pass through a heater or a heater and a cooler before it is held in overlapped surfaces of two rotating bodies, said material to be treated becomes a bulky product. Because left and right contrary twists are imparted thereto with the center of the bisecting line of said overlapped surfaces as a border, according to the present invention it is possible to obtain a bulky yarn having very little remaining torque. Again, at that time because the two rotating surfaces per se positively propel said long material in its proceeding direction, according to the process of the present invention it is possible to impart false twist to said long material to be treated almost without positively placing a tension on said material and a bulky yarn is prepared at a very high speed.

Again, when a continuous narrow film is drawn at a high draw ratio in a direction of its length and highly oriented in advance, and preferably further crystallized, because such film is easily split in a direction of its length by twisting and rubbing actions when the process of the present invention is applied to such a narrow film, it is possible to prepare a split fiber or split fiber yarn. Also, at this time, as in the case of preparing a bulky yarn, when a continuous narrow film is adapted to pass through a proper heater or a heater and a cooler before it is inserted between the two rotating surfaces, a bulked split fiber or split fiber yarn is prepared.

According to the present invention, as mentioned above, with the center of the bisecting line of overlapped surfaces of the two rotating surfaces as a border, is applied to a narrow film and twisting and rubbing actions from left and right contrary disections are imparted, it is possible to efficiently split said film, and because during the period said film is positively propelled in its proceeding direction by rotating force of said overlapped surfaces, split processing at a high speed becomes possible.

With reference to a process for preparing a bulky yarn and a process for preparing a split fiber according to the process of the present invention, detailed descriptions will be made later.

Upon practicing the process of the present invention, it is sufiicient to arrange long material to be treated so that it is inserted between overlapped surfaces of the two circular rotating surfaces of the same diameters and said material passes the bisecting line of said overlapped surfaces along the rotating direction of said overlapped surfaces, however, in actual operations the rotating bodies 15, 15' whose embodiment is shown in FIGS. 3 and 4 are preferred to the rotating bodies 5, 5 whose embodiment is shown in FIGS. 1 and 2. The reason is that in the present invention said material should be inserted and held tightly between said overlapped surfaces throughout the distance from the point A to the point B in FIGURES 4 to 6, namely the distance from the point where the material is inserted between overlapped surfaces to the point where the material is inserted between overlapped surfaces to the point where the material leaves said surfaces; and that in passing of said material through between the overlapped surfaces the contact resistance will decrease advantageously if the contacting area of said rotating surfaces except the passage for said material is reduced.

Therefore, as rotating bodies, rotating bodies'lS, 15' wherein on the surfaces of rims of bowl-shaped metal members 12, 12' having annular rims, and annular friction bodies are tightly mounted as shown in FIGS. 3 and 4, are recommended. At this time, however, axial distance of the rotating bodies 15, 15 having annular friction bodies 13, 13 must be properly provided.

In FIGS. 6 and 7, the mode of FIG. 4 is further made schematic, where outer peripheries and inner peripheries of overlapped surfaces of two rotating annular friction bodies 13, 13 are shown by curves p, p and q, q, respectively, whereby related positions of different axial distances of the rotating bodies 15, 15 having annular friction bodies are shown.

In FIG. 6, when distance of shaft centers 0, O of the two rotating bodies 15, 15' becomes smaller than the sum of inner radii of annular friction bodies 13, 13' (hereinafter referred to as r), namely, 2r, between crossing points H and I of inner peripheries of the respective overlapped surfaces of said annular friction bodies 13, 13', a space is brought about. As a result, a long material to be treated 6 severs at a point H from overlapped surfaces of the annular friction bodies 13, 13 and when it is held again in the vicinity of a point I by said overlapped surfaces, it receives strong impact of said annular friction bodies 13, 13' rotating in mutually different directions; said material will lose a correct proceeding path, AH-I-B and grave deficiencies like non-uniform treatment and yarn cutting often takes place.

Therefore, in the present invention, as shown in FIG. 7, relative position of the two rotating bodies must be so decided that distance between axial centers 0, 0' of the two rotating bodies (2b) may become at least larger than the sum of inner radii of the two annular friction bodies, 2r. Namely, it is necessary that the following formula should be satisfied In FIG. 7 showing disposition satisfying said formula, when points where outer peripheries p, p and inner peripheries q, q of annular overlapped surfaces of the annular friction bodies 13, 13 cross the central line 00' are made I, K, L and M, respectively, the narrowest width of overlapped surfaces of the two annular friction bodies 13, 13' becomes distance LM. In the present invention it is preferable that the line LM be made not smaller than transverse width (d) of a long material to be treated 6 when inserted and held by overlapped surfaces of said two rotating surfaces.

During rotation of the annular friction bodies 13, 13', because a part of a frictionally overlapped surface of the annular friction body 13 enclosed by a circle y having a radius of line CC and the internal periphery 9 does not contact the long material to be treated, this part has little wear, while a part between the circle y and the outer periphery q wears more by contact with the long material to be treated. Similarly, of the overlapped surface of the annular friction body 13', a part between a circle y depicted with line DC as a radius and the outer periphery p wears more.

Accordingly, upon practicing the present invention using annular friction bodies, it is especially advantageous to make width of the narrowest part of overlapped surfaces of the two annular friction bodies LM, as shown in the following formula, not smaller than width ofsaid long material to be treated inserted and held by said overlapped surfaces (which is expressed by d) and not larger than 2 times thereof, preferably, 1.5 times thereof.

d S LM2d especially dLM 515d Because the path of the long material to be treated somewhat fluctuates transversely, it is preferable to make LM not smaller than a, however, when LM becomes too large, a wearing part becomes large, this being undesirable. The value of said d can be experimentally decided.

By so doing, non-wear parts where the long material to be treated does not contact the overlapped surfaces, namely, surfaces enclosed by the circle y and the inner periphery q, and the circle and the inner periphery q, respectively are worn and removed by contact with the long material to be treated. The respective overlapped surfaces of the annular friction bodies 13, 13' respectively being equally worn, life of the rotating bodies is extended and it becomes possible to impart uniform treatment to the material to be treated 6 for a long period.

One embodiment of preparing a split fiber using circular rotating bodies used in the present invention will be explained with reference to FIG. 8.

In FIG. 8, 21 is a film shaped from a high polymer, for

instance, polypropylene, slit to a width fit to denier of a yarn desired, drawn to a proper magnification of 4-10X in a direction of length to sufficiently orient the film and wound up on a bobbin.

A drawn slit film 23 passes a tension compensator 24 via a snell wire 22 thereby being imparted with a necessary tension. The slit film 23 passes a yarn guide 25, entering a pair of circular rotating bodies 26 via a snell wire 22. The circular rotating bodies 26 are mutually pressed by a spring 27, imparting twist to the slit film while pulling downward the slit film, at the same time, imparting a rubbing action to the slit film between the overlapped surfaces of the rotating bodies. 28 is a winding device and a ring twisting machine or friction-type winder is used.

It is essential that the drawn slit film is made to pass between the overlapped surfaces of said two rotating bodies on substantially the bisecting line of said overlapped surfaces. By so doing it is possible to impart twist and rubbing actions simultaneously to the (drawn) slit film for the longest distance between the overlapped surfaces of the rotating bodies while it is pressed by the rotating friction bodies. Thereby the drawn slit film is sufiiciently split.

Said pressing is controlled to a desired amount by said spring 27.

If necessary it is possible to provide a heater or further a cooling device between the yarn guide 25 and the rotating bodies 26. In case a heater is provided, the split film being sufficiently tensioned and being heat set in twisted state within said heater, the slit film is sutficiently split, and somewhat bulky split fiber, not twisted but remaining u slight twisting inclination given at the time of heat :etting, is obtained. Due to rotating frictional action of he rotating bodies as mentioned above, because the split am is imparted with twists in different directions of Z 1nd S at AC and CB with the point C as a border, an :ffect similar to intertwisted yarn is brought about. As l result bundability of the obtained split fiber is enianced, and a characteristic split fiber capable of being voven without being imparted twist is obtained.

That is, according to the process of the present inven- :ion surprising advantages are that characteristic split ibers with bulkiness or a characteristic split fiber like ntertwisted y-arn unseen in a split fiber obtained by a :onventional process may be prepared.

As a split film used for preparing a split fiber by the )rocess of the present invention, a continuous thin, narow film consisting of a thermoplastic linear high polyner, sufficiently drawn and highly oriented is suitable. )raw ratio depends upon the kind of polymer; however, irdinarily 412 is adopted. However, selection of a lraw ratio suitable for the process of the present invenion will be easy for those skilled in the art. Also so as o facilitate splitting a fiber, crystallization to some extent s desirable. Especially to facilitate splitting by twisting 1nd rubbing actions a film prepared from a blend of at east two incompatible polymers, for instance, polyamide 1nd polyester is particularly suitable for the process of he present invention. As polymers used for the process if the present invention, homopolymers such as polyropylene, polyethylene, polyvinyl chloride, polyvinyldene chloride and polystyrene or a blend of polyester 1nd polyamide and a blend of polyvinyl chloride and iolystyrene may be cited.

As material of wearing parts of the rotating bodies used 'or preparing a split fiber in accordance with the present nvention, a synthetic rubber or natural rubber elastomer s suitable, especially urethane rubber having a large abraion resistance is most suitable. In this case, the hardness 5 60-100, preferably 80-90.

However, it is also possible to use for at least one otating body a rotating body mixed with powder of a ubstance having a high hardness, such as powder of an lbl'aSlVC and powder of silicone carbonate.

Upon splitting a continuous narrow film in accordance vith the process of the present invention, depending upon lroperties of a narrow film and operational conditions or splitting, the narrow film may be split to mutually ompletely separated fine fibers, or the narrow film may split to a continuous film having numerous fine splits, is a result the narrow film becomes a bundle of numerous ine fibers. In this specification, the former is named a plit fiber, while the latter is named a split fiber yarn, )Oth of which are useful for the object of the present in- 'ention.

Next, one embodiment of preparing a false twisted am using said friction rotating bodies will be explained vith reference to FIG. 9.

In FIG. 9, a continuous fibrous material 33 forwarded rom an original yarn pirn 31 is imparted with a preletermined tension at a tension compensator 34 via a nell wire 32, passing a heater 36 via a yarn guide 35, ntering the rotating frictionbodies of the present invenion 37, where tension and forwarding are imparted t aid fibrous material; 38 is a spring pressing a pair of ircular rotating bodies to each other thereby imparting l. necessary pressure to said fibrous material. The fibrous naterial coming out from the rotating friction bodies is vound up on a winding machine 39. If necessary, a coolng device may be provided between the heater 36 and the otating bodies 37.

By the rotating friction bodies the fibrous material is mparted with twist and action of forwarding due to the heory the same as that explained with reference to FIG.

When a false twisted portion of the fibrous material is limited to between A and C in FIG. 5, because the process becomes a process very similar to an ordinary spindle process, the obtained yarn becomes a bulky yarn wherein torque remains strongly in Z direction.

Whereas, according to the process of the present invention, a yarn once heat set in Z direction is untwisted to zero, and is further strongly twisted in the opposite direction and then untwisted. At this final twisting in the opposite direction, because the fibrous material is not heated, it is not possible to completely eliminate torque; however, it is possible to obtain a bulky yarn having torque far less than that of a yarn obtained by an ordinary spindle rotary-type false twisting machine.

What is considered a preferable condition for practicing the process of the present invention is that when the fibrous material enters the rotating bodies, the fibrous material is always tensioned to some extent.

In the present invention, it is necessary that the fibrous material, since it is inserted between the annular friction bodies until it comes out therefrom, should be inserted and held between the annular friction bodies without fail. In a case when the centers of the two annular friction bodies are approached and a space is brought about between the two annular portions, because the fibrous material is twisted prior to A, twisted shrinkage is brought about in the fibrous material. When the number of twist decreases at AC and said number becomes zero at C, the fibrous material is to be relaxed by that proportion, and unless the fibrous material is inserted and held at that place, the fibrous material will be forced out in a relaxed direction, it becoming impossible to stably practice false twisting operations and in that case a bulky yarn having weak torque cannot be obtained.

In contrast to an ordinary false twisted yarn which requires a step for eliminating torque for decreasing trouble at the time of unwinding of the yarn at a knitting or weaving machine, because a false twisted yarn obtained by the process of the present invention has very little torque, it has an advantage that such a step can be omitted. As another advantage, as will be shown in examples, the process of the present invention can obtain a processing speed which is very high as compared with an ordinary false twisting process.

A continuous fibrous material used upon preparing a false twisted yarn according to the process of the present invention consists of a thermoplastic linear high polymer and a polymer, for instance, polyester, polyamide, polyacrylonitrile, polypropylene and polyvinyl alcohol is used.

As the material for the friction parts of the rotating bodies used for preparing a false twisted yarn, an elastomer such as a synthetic rubber or natural rubber is suitable. Upon preparing a split fiber, a rubber having a high hardness is suitable for splitting film; on the contrary, upon preparing a false twisted yarn, from an object of imparting twist to the fibrous material, a soft rubber having a high coefficient of friction, and accordingly a low hardness, is suitable. On account of that, upon preparing a false twisted yarn, NBR is most suitable, especially NBR having a hardness of 40-80, preferably 5060 is most suitable. At this time, it is an effective mode of practice to supply an oiling agent to the rotating bodies for the purpose of reducing abrasion due to the low hardness of the rubber.

Upon practicing the process of the present invention, it is necessary to impart contact pressure to a film or fibrous material for the preparation of either a split film or false twisted yarn, the range of said contact pressure being 0.3-3.0 g./denier-cm., preferably 1. 02.0 g./denier-cm. Selection of a contact pressure most suitable for the operation is easy for those skilled in the art.

Hereinbelow examples will be described for explanatory purpose; however, these examples are for explanation, and not for limiting the present invention.

EXAMPLE 1 In this example an explanation will be made about a case of preparing a split fiber in accordance with the process of the present invention.

A low pressure (high density) polyethylene film was extrusion shaped, drawn to about 8 times the original length in a direction of length only in heated air and the drawn film was cut to a 0.015 mm. thick and 8 mm. wide slit film.

Using the apparatus shown in FIG. 8, this slit film was made a split fiber. Discs were a pair of flat disc-shape ones of urethane rubber having a hardness of 85 and outer diameters of 50 mm. The slit film was processed at a pressure mutually pressing said discs of 4 kg., tension at the film incoming side of 150 g., the distance between both centers of said discs of 28 mm. and at a film processing speed of 200 m./ min.

The obtained split fiber corresponded to about 1,000 deniers, each of the monofilaments constituting meshes being 30-40 deniers.

EXAMPLE 2 A stereospecific polypropylene film was extrusion shaped to obtain a 0.04 mm. thick broad film, which was continuously cut by a slitter to prepare a 34 mm. Wide slit film, which was continuously contacted with heated rollers thereby drawn about 9 times the original length in a direction of length to obtain an about 0.015 mm. thick and about 10 mm. wide film.

Using the apparatus same as that of Example 1, except discs this film was made a split fiber.

The discs had a pair of annular friction bodies of urethane rubber having a hardness of 90, having outer diameters of 50 mm. and inner diameters of 30 mm., the axial distance of the two discs was 30.8 mm.

The slit film was processed at a pressure mutually pressing said discs of kg., tension at the film incoming side of 200 mg;' and at a film processing speed of 250 m./min.

The annular friction body portions of the two discs were uniformly worn away. The worn amount per kg. of the treated amount was 0.005-0.01 mm.

The obtained split fiber corresponded to about 1,200 deniers, each of the monofilaments constituting meshes of about 25-35 deniers.

The obtained split fiber had a tenacity of 3.5 g./de. an an elongation of 18% EXAMPLE 3 As a material the slit film described in Example 2 was used.

Discs were a pair of annular friction discs of urethane rubber having a hardness of 90, having outer diameters of 54 mm. and inner diameters of 25 mm. and the axial distance of the two discs was 32 mm.

The slit film was processed at a pressure mutually press ing said discs of 4 kg., tension at the film incoming side of 300 g. and at a film processing speed of 260 m./min.

The obtained split fiber was about 1,200 deniers, each of the morlofilaments constituting meshes of about 25-35 deniers.

Here the obtained split fiber was re-processed in order to make the monofilaments fine.

The split fiber was processed at a pressure mutually pressing said discs of 4 kg., tension at the split fiber incoming side of 200 g. and at a processing speed of 300 m./min.

As a result, a bundable soft split fiber having a tenacity of 3 g./de. and an elongation of 20%, each of the monofilaments constituting meshes of said split fiber of about -25 deniers was obtained.

EXAMPLE 4 In this example description will be made about a process for preparing a bulky split fiber.

The film and discs used were same as those described in Example 2.

A heater for fixing twist was provided before the discs, the type of said heater being of contact type, said heater being of a bow shape, 1,500 mm. long and the heating part thereof was divided into two stages.

The film was processed at a pressure mutually pressing said discs of 4 kg., tension at the film incoming side of 200 g. and tension at the film winding side of 50 g. The distance between both centers of the two discs was 31 mm. and the film processing speed was 150 m./min.

Temperature of the heater was 220 C. at a first stage and C. at a second stage, and temperature of the film at a speed of,, m./min. was substantially l20130 C.

Number of false twists at the heater was 400 T/M under the aforementioned conditions.

The obtained split fiber was bulky, having an alternately twisted shape, each of the monofilaments constituting meshes of 30 40 deniers.

The characters of the obtained split fiber were:

Tenacity g /den 3.5 Elongation percent 22 Wet heat shrinkage (boiling water) do 1.5 Dry heat shrinkage (120 C.) do 3-4 Density of warp and weft were both 15 per inch and a fabric of a good quality was obtained, which could be used as a primary backing of a tufted carpet.

EXAMPLE 5 In this example an explanation will be made about a case of preparing a woolly yarn in accordance with the process of the present invention.

A yarn used was a nylon semi-dull 1,050 denier/68 filament multifilament.

The discs were a pair of fiat disc-shape of urethane rubber having a hardness of 70, having outer diameters of 54 mm. The multifilament was processed at a pressure mutually pressing said discs of 4 kg., tension at the multifilament incoming side of 50 g., the center distance of the two discs of 26 mm. at a multifilament processing speed of 80 m./min.

As a heater, the one employed in Example 4 was used, temperature of a firststage thereof being made 230 C. and temperature of a second stage was made 180 C.

Number of false twists of the multifilament at the time of passing the heater was 750-800 T/ M and by providing a cooling device after the multifilament passed the heater, a bulky crimped yarn was obtained.

Said bulky crimped yarn had less torque as compared with a woolly yarn obtained by the conventional spindletype false twisting process, the same being used for interior products such as carpet or upholstery.

EXAMPLE 6 In this example an explanation will be made about a case of preparing a woolly yarn of a fine denier in accordance with the process of the present invention.

A yarn used was a nylon semi-dull 70 denier/24 filaments multifilament.

Discs used were a pair of annular bodies of nitrile rubber having a hardness of 50, having outer diameters of 54 mm. and inner diameters of 25 mm.

The multifilament was processed at a pressure mutually pressing said discs of 5 kg., tension at the multifilament incoming side of 10 g. distance between both centers of the two discs of 25.12 mm. at a multifilament processing speed of 180 m./min.

The heater used in Example 5 was used.

In this case size of the multifilament in twisted state was about 0.1 mm. in diameter.

Number of false twists at the time of passing the heater was 2,900 T/M-3,000 T/ M and by compulsorily cooling the multifilament after being heated, a bulky crimped yarn was obtained.

EXAMPLE 7 This example also relates to a case of preparing a fine denier woolly yarn in accordance with the process of the present invention; however, the yarn used was a polyester semi-dull 75 denier/36 filaments multifilament.

Discs were of nitrile rubber having a hardness of 50, having a pair of annular bodies having outer diameters of 62 mm. and inner diameters of 25 mm.

The multifilament was processed at a pressure mutually pressing said discs of 5.5 kg, tension at the multifilament incoming side of 110 g., tension at the multifilament outgoing side in front of a winding machine of 6 g., the distance between both centers of the two discs of 27 mm. and at a multifilament processing speed of 200 m./min. The heater employed in Example was used. Temperature of the heater was made 260 C. at a first stage and 210 C. at a second stage.

Number of false twists of the multifilament at the time of passing the heater was 3,2003,300 T/M and onto the disc surfaces cooling water mixed with a few percent of an oiling agent was applied continuously.

By compulsorily cooling the multifilament after heating, a sufficiently bulky crimped yarn was obtained.

What is claimed is:

1. A process for false twisting a continuous thin, narrow film or continuous fibrous material consisting of a thermoplastic linear high polymer, characterized by passing said film or continuous fibrous material between frictionally overlapped surfaces of two rotating surfaces of the same diameter rotating in mutually different directions while frictionally contacting face by face along the rotating direction at said overlapped surfaces substantially on a line bisecting said overlapped surfaces.

2. A process according to claim 1 wherein parts of ;aid rotating surfaces contacting said continuous narrow film or continuous fibrous material are composed of a synthetic rubber.

3. A process according to claim 1 wherein said continuous narrow film or continuous fibrous material is tightly inserted between said overlapped surfaces through nut the entire period since it is inserted and held between the overlapped surfaces of said two rotating bodies until it parts therefrom.

4. A process for false twisting a continuous thin, narrow film or continuous fibrous material consisting of a thermoplastic linear high polymer which comprises passing said film or continuous fibrous material between overlapped surfaces of two annular friction bodies having the same lengths of inner and outer diameters rotating in mutually different directions while contacting face by face along the rotating direction of said friction bodies substantially on a line bisecting said overlapped surfaces, characterized in that distance between centers of the rotating shafts of said two annular rotating bodies (2b) is made not smaller than the sum of the inner radii thereof (2r).

5. A process according to claim 4 wherein diiference between centers of the rotating shafts of said annular rotating bodies (2b) from the sum of the internal radii thereof (2b), distance LM is not smaller than the width (d) of the narrow film or continuous fibrous material and not larger than two times thereof (2d), preferably 1.5 times thereof (15d).

6. A process for preparing a split fiber from a continuous thin, narrow film of a thermo-plastic linear high polymer, crystallized and drawn in the direction of length only, which comprises passing said film between frictionally overlapped surfaces of two rotating surfaces of the same diameter, rotating in mutually different directions, while frictionally contacting said film face-toface at said overlapped surfaces substantially on a line bisecting said overlapped surfaces.

7. The process of claim 6 wherein said split fiber is produced as a bulky split fiber by a process which comprises an additional step of passing said film through a heating zone before said film is inserted and held between said overlapped surfaces.

8. The process of claim 1 wherein a bulky yarn is produced by passing a continuous multifilament yarn through a heating zone prior to inserting and holding said yarn between said overlapped surfaces and passing said yarn therethrough.

References Cited UNITED STATES PATENTS 2,522,332 9/1950 Abbott 5777.4 XR 2,943,433 7/1960 Van Dijk 5777.42 XR 3,003,304 10/1961 Rasmussen 57157 3,156,084 11/1964 Van Dijk et a1 5777.4 3,373,554 3/1968 Raschle 5777.4 3,382,663 5/1968 Frielingsdorf 57167 XR 3,395,525 8/1968 Eddy 57167 XR MERVIN STEIN, Primary Examiner WERNER H. SCHROEDER, .Assistant Examiner US. Cl. X.R. 5777.4 

